Modern telecommunications networks provide access to many devices which may be controlled by a network user. For example, a caller on a telephone network may access and control voice messaging systems, information delivery systems, order taking systems and personal banking systems by using touch-tone signals sent over the telephone network. However, touch-tone signaling is not always available, particularly when rotary wireline telephone equipment is used. In other cases, touch-tone signaling is not desirable. For example, when a cellular phone is used, the signal may be intercepted and any information communicated by that signal may be obtained by unauthorized persons.
FIG. 1 is an exemplary block diagram of a conventional system 100 for controlling a destination system, such as an automated information delivery system, a voice mail system or a home banking system. User station 102 is conventionally connected to a local exchange carrier network (LEC) 104a over a link 103. As is well known, LEC 104a is connected to an inter-exchange carrier network 106, which is likewise connected to an LEC 104b. Destination system 114 is conventionally connected to LEC 104b.
A user who wishes to access and control destination system 114 places a call from user station 102 to destination system 114. User station 102 is typically a telephone, either landline or mobile. The call is connected to a local exchange carrier (LEC) network 104a over link 103. If the call is long distance, LEC 104a is connected to inter-exchange carrier (IEC) network 106. IEC network 106 routes and completes calls to and from IEC network 106 and LEC network 104b. Networks 104a and 104b may be the same network or different networks. If the call is not long distance the call may be routed entirely within a LEC network. In any case, the call is completed to destination system 114. The user then transmits signals, which typically are touch-tones generated by pressing digits of the telephone, to control destination system 114. For example, the user may step through the menus of an information delivery system, operate a voice mail system or perform transactions in a home banking system.
However, problems arise with system 100. If user station 102 is a rotary telephone, no touch-tones are available and the user is unable to control the destination system. If user station 102 is a mobile telephone, link 103 includes a wireless channel, which is susceptible to interception by unauthorized persons. Thus, for security reasons, it may be undesirable to transmit touch-tone signals over a cellular phone channel. Consequently, what is needed is a way to transmit signals to control network connected devices which is secure and is always available